As coastal states move closer toward adopting a new management plan for Atlantic menhaden, a new assessment continues to offer a mixed outlook on the health of the stock.

Recently analyzed figures from last year’s catch data indicate that the “spawning stock” — an estimate of the adult population — has fallen sharply for the second straight year.

Doug Vaughan, a National Marine Fisheries Service biologist who makes an annual menhaden assessment, estimated the spawning stock was 32,800 metric tons last year.

That is below the long-term average of 40,000 metric tons, and less than half of the 87,000-metric-ton spawning stock that was along the coast in 1997, according to a revised assessment by Vaughan for that year.

At the same time, though, a preliminary estimate of the number of young fish that joined the coastal menhaden stock shows an increase for last year. Vaughan estimated that 2.7 billion menhaden were “recruited” into the coastal stock in 1999.

If that number holds up, it would be the first time since 1995 that the number of young fish was above a key threshold level of 2 billion. But it would still remain below the long-term average of 3 billion.

Vaughan cautioned that the estimate of young fish could be high. He calculates the number of fish of various ages based on catch records from the menhaden fishery.

Last year, the industry caught an unusually high number of young fish — possibly because heavy storms mixed schools of young and old fish together — which could skew age estimates. Catch records from this year and next year will help to give a clearer estimate of how many fish actually “recruited” into the population in 1999, he said.

For reasons that are unknown, the menhaden stock has suffered from a series of years with poor reproduction, raising concern about the health of the stock and its impact on other fish that rely on menhaden for food.

Vaughan said that an increased number of recruits would confirm anecdotal reports of large numbers of young menhaden being seen last year in New England, and — to a lesser degree — off North Carolina. But recruitment still appeared poor in the Chesapeake Bay, he said.

The future health of the stock, Vaughan said, depends on whether recruitment continues to increase enough to replenish the adult population.

“Everything seems to hinge on what kind of recruitment we’re going to get,” he said. “If we get a couple of years of moderate recruitment, then I think we’ll see the spawning stock in a couple of years start to go back up again. But if we just see one good year and then have a couple more bad years of recruitment, then the spawning stock will continue to decay.”

The management of menhaden has become increasingly controversial in recent years as recreational fishermen and others have complained that the commercial menhaden fishery is catching too many of the fish, which provide food for larger predators such as striped bass, weakfish and blue fish.

The Atlantic States Marine Fisheries Commission, a panel that represents all East Coast states and is responsible for developing management plans for species that migrate across state lines, is expected to release a revised menhaden management strategy for public comment later this year. A new strategy could be adopted by year’s end.